It's a magnet rock… That kinda seems normal-ish.
(Reads rest of SCP)
Okay, that could be considered as a SCP.
So if connected to enough power, this could make quite a doomsday weapon. This could easily be Euclid if it would be harder to contain.
Apart from the occasional grammar issue, This sounds like a great start to a good SCP. Keep on it!

grockstar124, this advice is not only unhelpful, but it is also misleading. This sort of SCP (generic magic object, violent without narrative necessity, excessive test logs to the point of uninteresting extraneous detail) is not what current standards of the site encourage writing. Furthermore, if you're going to say there are grammatical issues, at least point out a few specific ones that you found so the author doesn't have to scour the entire page themselves. The comment about object class is irrelevant—there's no need to encourage people to write Euclid class SCPs or laud them for writing dangerous Safe SCPs that approach Euclid (because, it's common knowledge that Euclid objects are more difficult to contain than Safe. That's an inherent property of Euclid objects).

This is not the first time staff has had to address this behavior.

This is your official warning. Wait for more experienced members to comment on new SCP drafts; do not post first or you may face membership revocation and possibly a ban from the site.

This staff post is closed. Do not respond to this post if you're not a staff member.

Ookay.
Basically, this is a rock which generates a magnetic field as a function of applied current. It's better than most first drafts I have seen these days, but for Bast's sake, there's no hook, and the science is rather poor at times.
Actually, lemme do a line-by-line to draw attention to some things

It appears to be a rock but is a spaceship? Also, the "medium sized" is unscientific and useless - I don't know what a medium sized rock is because unlike animals and plants, rocks don't really come in fixed sizes.

. SCP-XXXX’s surface is smooth, black, and dotted with orange discolorations characteristic of small veins of iron.

Very good. I like this sentence.

SCP-XXXX weighs 612 kg with an estimated volume of 16000 cm3 making it nearly 5 times as dense as pure iron.

First of all, why is the density not listed, instead of total volume? Why is there a comparison to pure iron which is, as of the context, completely irrelevant? (If its composition would be pure iron, but its density differed, that'd be an example of a case where I'd care.)
Furthermore, why was no chemical analysis done to determine composition?

SCP-XXXX was found in the ████████ desert in South-Western United States, by a group of hikers. At the time of discovery SCP-XXXX was coated in iron filings, presumably stripped out of the nearby dirt

That's an odd presumption. Does dirt regularly contain iron fillings?

Anomalous characteristics were first discovered when the house of one of the hikers collapsed during the night. The cause of the collapse was determined to be a structural failure in the beams supporting the roof, near where SCP-XXXX was later recovered by the foundation

This is completely implausible. Why would the Foundation investigate a random house falling down? Never mind ,how did this make it fall down?

Initial testing revealed a magnetic field of 3-17 millitesla's extending an average of 3 cm’s from the objects surface, equivalent to a strong refrigerator magnet.

This is not the sort of a magnet that breaks I-beams

testing facility SCP-XXXX was accidentally dropped on a floor-level lighting fixture, causing it to break and expose SCP-XXXX to the live wire. Power to the facility was lost 3 seconds later, and a recovery team was dispatched to investigate

Allright. So dropping it on live wire has power passing through it, never mind, a lot more than through the original wire section. So, somehow , this has negative ohmic resistance. I'm actually intrigued.

All ██ dead personnel were found with torn skin and broken bones, as well as missing teeth and organs. SCP-XXXX was found covered in extremely fine magnetic powder as well as other metal objects.

Even if it did what you say it did later, it'd still not work like this.

It is theorized SCP-XXXX is able to draw in electrical power and convert it into a strong magnetic field. Tests were done at varying volts and amperes to find any patterns in SCP-XXXX’s behavior.

Nope. It draws in current, if anything and not power, and the current generates a magnetic field.
Also, tests were done varying the potential difference or current across SCP-XXXX, not the least because they aren't independent variables.
But, again. A volt-ampere characteristic of this thing would be interesting. Does it kick out fuses the moment it's connected to a circuit? (zero ohm hypothesis). What does it do if you connect a loop across it, then? Or, does the negative resistance still need an initial "kick" - a driving voltage to get electrons moving through? What does AC do? Even more interesting… most things, this is two way. Can we induce huge eddy currents through this by a small magnetic field applied the right way? This has a potential to be a very hard science, cool SCP, though sadly, that by itself won't likely hook most people (though my personal taste, it would).

3.74 Amperes magnetic field extending exactly 1 mm from surface at 4 kilotesla, stable for approximately 3 seconds until power supply was drained completely.

How do you "drain" a constant current, mains-run power supply?

Note: It appears that at high amperages SCP-XXXX is able to create a magnetic field strong enough to pull on the iron in red blood cells with enough force to rip them from the body. Further biological testing is discouraged

This is massive bullshit - magnetic fields do not do that, as iron in blood is a part of hemoglobin, which is a structure no more ferromagnetic than rust or iron sulphate. I'm honestly hardly sure what large magnetic fields would do to a human body (or animal) but first of all, it should be you to research it as you're the one writing about it.

Final verdict - this isn't on a bad track, but needs a hook, and needs more science.

I'm honestly hardly sure what large magnetic fields would do to a human body (or animal)

Wellp… If it's strong enough, it can cause molecular bonds to fail. A magnetar, whose magnetic field is measured in gigateslas, could absolutely shred a person. Of course, a field that strong would also cause the destruction of Earth as we know it.

Well, yes - but that sort of thing will cause most matter around to break, kinda like an electric field strong enough will rip electrons from atomic nuclei, also shredding whatever.
I don't think this one has such an output, though.

I've always had a fondness for things that break the rules of physic in interesting ways. Unfortunately a deeper knowledge of electricity and magnetism is really needed to make the science here interesting enough to hold my attention. This is compounded by the fact that this article doesn't have any thing else going on (e.g. it doesn't exactly evoke a strong emotional response or have a gripping plot)

Also a few smaller issues:

16000 cm^3

cm cubed

5 times as dense as pure iron

Iron has a defined density there is no need to specify that it is "pure". (Even if you needed to specify this "elemental iron" would probably be the way to go)

and temporarily stored in a broom closet

This seems oddly casual for something that they think destroyed a house. Also I'm pretty sure the Foundation keeps even well studied harmless anomalous items in more secure setting then a broom closet.

Note: Incident will henceforth be referred to as XXXX-I-000

For whatever reason numbering of incidents usually seems to start at 001. This is not a rule or anything, it just makes this stand out as a bit odd.

The whole incident-000 is a little silly. If you are moving a 600 Kg object around the facility you would almost certainly be using a wheeled cart and you probably would have strapped the object to the cart. Given this I find the fact that they dropped it noticeably jarring to read. Also smashable floor lighting sound like a bad idea on a ridiculous number of levels.

Finally I'll note that red blood cell while not ferromagnetic are paramagnetic and as such it is not inconceivable that they might react to a big enough field.

Oh cm3 is the way to write it (which I probably should have said) I was just trying to point out that they gave a 1 dimensioned measurement (cm) when talking about a volume. (no cubic centimeters, no cm3, no centimeters cubed just cm).

Also this article is somewhat inconsistent in its use of spacing between numbers and there units. E.g.